Thermostat.



R. F. MASSA.

THERMOSTAT. APPLICATION FILED NOV. n, 1913.

Patented July 13, 1915.

I UNITED STATES PATENT OFFICE. v

3031mm 1'. MASSA, or ram: WAYNE, INDIANA, ASSIGNOR TO 11'. w. JOHNS-MANVILLE COMPANY, A CORPORATION or NEW YORK.

To all whom it may concern Be it known that I, RoBnRT F. MASSA,- acitizen of the United States of America, residing at the city of FortWayne, Allen county, State of Indiana, have invented certain new anduseful Improvements n Thermostats, of which the following is aspeclfication.

My invention'relates to apparatus for automatically operatingtemperature control ling devices, and isspecificallydeslgned to producea sensitive and positlvely acting thermostatic mechanism for alternatelyopening and closing an electric circuit. The usual form of device forth1s. purpose, 1n which a switch memberis moved solely by a thermostaticmember, is defective in that the action is slow and hesitating, andresponsive only to considerable variations of temperature. Thevacillating action of the device at critical temperatures produces an inur1- ous sparking at contact points, and when magnets have beep used tomake the contact iy/flfey have interfered action more pos1 with thesensitiveness of'the apparatus, the

movable armature freezing to the magnet in certain positionsof thethermostat.

My invention overcomes these diflicultles Y by a special arrangement ofmagnetic field,

armature and contact members such as illustrated in the accompanyingdrawing, whichdiagrammatically illustrates the best form of apparatusfor embodying my mventlon at present known to me. Referring to thedrawing, A,.1s a thermostatic member formed in the usual way of twoelastic strips of metals having different coefficients of expansionunder heat, such as steel and brass, welded or otherwise fastenedtogether and coiled into a spiral. The lnner endof the spiral is rigidlyfastened at B,to a non-conducting base, such as the slate slab C. Theouter and free end of the spiral carstrip G, are attached. H, is acontact member formed of any non corrod1ng metal, car- ,ries a barD',-to the outer end of which a soft iron armature E, and a light springried by spring G.

F, is a magnet, preferably a permanent magnet of horse shoe form, heldto base C, by clips L, L, so that the armature E, Wlll move toward. andfrom the center of the magnetic field of force as the coil A, unwinds orwinds up under the action of varying temperature.

Specification of Letters Patent.

THERMOSTAT.

Patented July 13, 191 5.

J is a brass screw adjustably mounted in a pm, or other support on-baseC, and havlng a t1p K, of material similar to H.

M, represents a binding screw set in base C, and electrically connectedto movable contact member H, as by a wire X, indicated in dotted linesextending under base C, to pin B. Another binding screw N, iselectrically connected to stationary contact member K, as by wire Y,indicated in dotted lines, extending under base 0, to pin I. Anysuitable work circuit is indicated at W, includinga source of current,Q,.and a translating device, such as motor S. 7

Such being the. arrangement of the apparatus, the operationis as followsAssuming that S, is a solenoid having a core R, normally pulled out byspring T, and connected to a switch .U, which controls the motor circuitof (not shown) and that-said refrigerating machine controls thetemperature in the room where the thermostatic member A, is. placed, thesupporting pin B, is soadjusted that when the desired .temperatureexists in the room, the armature. IE, will be located in the weakerouter zone of the magnetic field created by the magnet F and thecontacts H, and K, will be separated. The circuit W, will thus be openand the core R, of solenoid S, extended by spring T, to open the switchU. The thermostatic. member A, is then so adjusted that upon a slightrise of temperature the coil A, will unwind (or expand) sufficiently tomove armature E, into the more intense zone-of the magnetic field ofvaried intensity produced by magnet F. Thereupon the increased magneticattraction promptly'pulls the armature farther toward the magnet untilcontact members H, and K, meet and close the circuit. The solenoid S, isthen thrown into operation to close the switch and the refrigeratingapparatus (not shown) reduces the temperature to the predeterminedpoint. Thereupon the elastic tension of the spiral A, which has beenproduced by the flexing of the spiral when the armature was pulled overby the magnet, is increased by its tend ency to contract under the.influence of the lower temperature, and when the magnetic attraction isoverpowered by this elastic pull of spiral A, and that of the spring G,

the armature moves outv into the weaker portion of the field. Thereupontheelastic stress promptly overcomes what is left of the magnetic pull,and the armature moves-- quickly to a farther distance suflicientseparate contacts H, and K. At the crit1- cal temperature there is awavering or vacillating of the armature E, butno sparking occurs as thespring G, keeps the contacts together. Before the armature moves. farenough to, open the circuit it has reached such a weak zone of themagnetic field that the" elastic tension of A, pulls it quickly away andthe break between the contact members is quick and positive. When thecircuit is opened the solenoid becomes dead,

spring R, pulls the core T, out, opening switch U, andzthe refrigeratingmachine I stopsuntil a slight rise of'temperature again causes thearmature to approach the center of intensity of the magnetic field andthe operationfirst above described is repeated.

With my invention 1' am able to reduce the range of temperaturevariation to half a degree Fahrenheit, and by eliminating all Y sparkingI produce a thermostat which will operate indefinitely'withoutsubstantial deterioration. .As the armature never qulte touchesthe magnet poles, there is no op- -G, the degree of sensitiveness of theinstrument'can be varied so that it'will respond to a minimumchangeoftemperature, or

permit a widerflvariation without setting I the apparatus in motion.Alsov adjustment of the relative positions of the magnet and thethermostatic member, determines the temperature at which the apparatuswill operate.

.Of course other forms of magnet or magnetic field, thermostatic'membersand contact members, could be substituted forthose illustrated, withoutnecessarily departing from the principle of my invention as aboveexplained. So long as a magnet and armature, one of which is fixed andthe other movable, are employed with a spring contact to preventchattering, the other elements of the structure illustrated may bemodified in many ways to suit varying conditions or requirements.

Having described my invention, I claim: 1. In an automatic temperaturecontrolling device the combination of a flexible, elastic thermostaticmember, rigidly fastened at one point, an armature carried on 2 withinthe line of travel of the armature when moved by the effect of varyingtemsaid thermostatic-member at another point, a magnetic field of variedintensity located perature on the thermostatic member, a contact memberlocated near the point. of

said thermostatic member at another point,

Y tact member located near the point of great: I 'est' intenslty of thefield, a cooperating greatest intensity of the field, a cooperatingcontact member carried by the thermostatic member, and an electriccircuit connected to said contact members. I

- 2. In'an automatic temperature controlling device the combination of aflexible, v elastic thermostatic member, rigidly. fastened at one point,an armaturecarried on a magnetic fieldof varied intensity located withinthe line of travel of the armature when moved by the effect of varyingtemperature onthe thermostatic member, a conspring supported contactmember carried'by the thermostatic member, and an electric cir- I cuitconnected to said contact members.

3. In an automatic temperature control-iv ling device the combination ofa s irallyfiggg coiled thermostatic member held rigidly at that endwhich forms the center of the coil, an armature and a yielding contactmember carried by the free end of the thermostatic member, a permanentmagnet so located that the armature approaches its poles when thethermostatic member moves in one direction, an adjustable stationarycontact member so located that the other contact meme ber touchesit-when the armature nearly touches the magnet poles, andan electriccircuit the terminals of whichjare connected to said contact members. i

4. In an automatic temperature control ling device the'combination witha thermostatic'member adapted to be flexed'b varia-ftions of temperatureand rigidly astened at one end, of-an armature and a contact membercarried by the movable portion of said thermostatic member, astationary'magnetic field of varied intensity into and ,out of which'thearmature may be carried by I flexure of the. thermostatic member, astationary contact member so located as to] touch the moving contactmember onl when the armature a proaches the point 0 greatest intensity 0the magnetic field, and an electric circuit in which said contact'members are included. i

5. In an automatic temperature controlling device the combination of amagnetic field of varied intensity, a movable arma-T ture, athermostatic member adapted to; move saidv armature toward and from thecenter of intensity of said field, a movable no contact memberoperatively connected to said armature, a stationary contact member solocated as to 'touch the movable contact. I member onlywhen the armatureapproaches] the center of intensity of said field, and an electriccircuit in which said contact mem- V bers are included.

6. In a thermostatic device for control l :ling an electric circuit, thecombination of a stationary magnet, a movable thermost'ati-f tactmember, and an elastic contact member carried by the magnet and adaptedto strike the stationary contact member when the armature approaches themagnet poles, and prevent its further motion toward and contact withsaid poles.

8. In an automatic temperature controlling device the combination of athermostatic member, an armature controlled by said thermostatic member,a magnetic field of varied intensity located in the line of travel ofthe armature when moved by reason of temperature changes, a contactmember independent of the thermostatic element,

and a cooperating contact member controlled by the-armature, at leastone of said contact members being elastically mounted with reference toboth magnet and armature.

9. In an automatic temperature controlling device the combination of amagnet and armature movable one with reference to the other, athermostatic member having a motion controlling connection with-one ofthe two first'mentioned elements, and two. contact members, one of whichis movable by the thermostatically controlled member, at least one ofsaid contact members being elastically mounted with reference to bothmagnet and armature.

10. In an automatic temperature controlling device the combination of amagnet and armature movable one with reference to the other, athermostatic member having a motion controlling connection with one ofthe two first mentioned elements, and means for adjusting the normalrelative positions of said thermostatic member and the stationaryelement, together with two contact members,

one of which is movable by the thermostatic member, at least one of saidcontact members being elastically mounted with reference to both magnetand armature.

11. In an automatic temperature controlling device the combination of amagnet and armature movable one with reference tothe other, athermostatic member having a motion controlling connection with one ofthe two first mentioned elements, and means for adjusting the normalrelative positions of said thermostatic member and the stationaryelement, together with two contact members, one of which is elasticallymounted on the thermostatic member, while the other has an adjustablestationary mounting.

ROBERT F. MASSA.

Witnesses: V

KATHERINE MCCABE, ELLA L. BEVERFORDEN.

